The present invention relates to a surgical instrument for clamping and severing the umbilical cord of a newborn infant and a methods of constructing and utilizing such instrument. In particular, this invention relates to an instrument that first clamps and immediately afterwards cuts the umbilical cord all in one continuous action. The instrument can also be used to clamp and cut any artificial or natural deformable tube that is capable of being clamped and then severed, particularly tubes containing flowing fluid such as body fluid or water. Examples of such tubes are umbilical cords, infusion tubes, dialysis tubes, irrigation tubes, etc.
The umbilical cord is a flexible tube that connects the fetus to the placenta and contains two arteries and one vein that carry blood in and out between the fetus and the placenta.
A common method today for clamping the umbilical cord prior to cutting it is to use V shaped clamps. These clamps are fabricated from flexible material and comprise a pair of arms joined together at one end by an integral hinge-forming loop of substantial diameter. The free ends of the arms terminate in head portions that are normally spaced apart. The arms are movable towards each other by a compressive force. The head portions of the V clamps have means for locking the arms when pressed together thereby clamping the umbilical cord therebetween.
After an infant is born, the umbilical cord is clamped by a first V clamp as close as possible to the infant and then cut. In order to avoid blood squirting out of the open end of the cut cord another common method uses two V clamps. The second clamp is clamped about 5 centimeters towards the placenta and a pair of scissors is used to cut the cord between the clamps.
Another method is to use four V clamps, where the third clamp is placed about 10 centimeters from the second clamp and the fourth clamp is placed about 5 centimeters further towards the placenta. The umbilical cord is then cut twice, first between the first and second V clamps and then between the third and fourth clamps. This way a sausage like tube, of about 10 centimeters long, is formed containing infant""s blood which is then used for testing.
The above described methods still have some disadvantages since they require precious seconds to clamp and cut the umbilical cord, seconds than may make the difference between a routine delivery or one complicated by serious lung problems.
Various devices and procedures have been developed to clamp and cut the umbilical cord.
U.S. Pat. No. 3,150,666 discloses a device for clamping one end of an umbilical cord and then applying an elastic band around the umbilical.
U.S. Pat. No. 3,166,071 discloses a device for simultaneously applying two spaced umbilical cord clamps and severing the umbilical cord there between.
U.S. Pat. No. 4,026,294 requires two actions, first to clamp and then open the scissors to move them, and then to cut.
U.S. Pat. Nos. 4,428,374 and No. 4,648,401 disclose simultaneously clamping and severing the umbilical cord. This simultaneous action is dangerous as previously explained.
U.S. Pat. Nos. 4,556,058, 4,469,346, 4,576,165 and 4,572,181 disclose devices that are not scissors shaped and their action is by means of a vertical movement which first clamps the umbilical cord and later severs it by moving a blade through the clamped cord. This procedure requires bringing the cord into the device manually with one hand and using the other hand to operate the instrument. In a scissors action, only one hand is needed and the other hand is free.
U.S. Pat. Nos. 4,716,886 and 4,938,215 do not use a scissors like instrument to clamp and sever the umbilical clamp. They use a shear pin between the two clamps that is severed by the blade as well, enabling the two clamps to separate. Such a shear pin is dangerous as it might break into smaller pieces endangering the infant.
U.S. Pat. No. 4,870,965 discloses a double upper handle, the first one to clamp the clamps and the second to eject the clamped umbilical cord from the device.
U.S. Pat. No. 5,009,657 also simultaneously clamps and severs the umbilical cord. A tab (62), formed on the central section of the clip, is used to release the clamps from the device after the cord is severed and not before the act of severing as suggested in this invention.
U.S. Pat. No. 5,127,915 discloses simultaneously clamping and severing the umbilical cord. The device disclosed therein allows release of the clamp immediately after the severance, again, not before the act of severing as invented in this invention.
U.S. Pat. Nos. 5,190,556, 5,415,665, 5,520,699 and 5,575,796 disclose instruments that are not scissors like, and their main objective is to collect the blood from the mothers end of the cord.
U.S. Pat. No. 5,462,555 also discloses an instrument that is not scissors like and that does not use handles to clamp and later sever the cord.
U.S. Pat. Nos. 5,584,840, 5,667,516 and 5,817,103 disclose instruments that are also not scissors like.
U.S. Pat. No. 5,676,672 of suggests a method to clamp and sever the umbilical cord using a tube like device, which does not resemble scissors.
U.S. Pat. No. 5,591,173 discloses a scissors like apparatus for clamping a compressible body prior to cutting it, such as an umbilical cord, which is different from the device of this invention.
The major problem with scissors-like devices is that there is always the risk that the cord will be severed before it is completely clamped and squashed. It is essential that firstxe2x80x94the umbilical cord be safely clamped and only afterwardsxe2x80x94that it be cut. Some instruments clamp and sever the umbilical cord simultaneously and this is very dangerous. If the clamps are not yet completely closed before the cutting action, blood will spurt out of the infant""s side with all its consequences. In a worst case scenario, the umbilical cord will be cut before the clamps are completely closed and secured. In this case, the ends of the cord may slip out of the clamp leaving the severed cord open allowing blood to burst from the infant end. In the case of scissors-like devices, which have the V clamps mounted on the scissor jaws, the clamps can be completely closed, however, further movement of the handles on the other side of the pivot to completely close them is not possible. This inability to continue the movement of the handles after the clamps are securely closed prevents the clamping and severing of the cord in one continuous action.
The World Health Organization (WHO) has emphasized in it""s three latest publications regarding childbirth (xe2x80x9cCare in Normal Birth: a practical guidexe2x80x9d, 1999; and xe2x80x9cEssential Newborn Care, Report of a Technical Working Group (Trieste, 25-29 Apr. 1994)xe2x80x9d; and xe2x80x9cCare of the Umbilical Cord, A review of the evidencexe2x80x9d 1999) that only after secure clamping of the umbilical cord has been completed, the cord should be cut.
It is a preferred object of the current invention, to provide a scissors like surgical instrument that will clamp the umbilical cord and sever it-near the clamp. By exerting pressure on the handles of the instrument two operations will be performed by the jaws at the other end of the pivot. The V clamp held in the jaws will clamp the cord securely closed and only afterwards will the blades cut the cord when xerting additional pressure on the handles. As stated before, it is essential that first the umbilical cord is safely clamped and only afterwards that it will be cut.
Our invention consists of a scissors like device onto which on the blades side is attached at least one clamp in a V shape, or two clamps in a V shape, one on each side of the scissors jaws. The V shaped clamps are fabricated of semi-rigid material and comprise a pair of arms joined together at the apex of the V by an integral hinge-forming loop of substantial diameter. The free ends of the arms are normally spaced apart and terminate in head portions. The head portions of the V clamps carry means for locking the arms together in the clamping position. The arms are movable towards each other by a compressive force to clamp the umbilical between them.
At least one blade is positioned on the jaw of the scissors adjacent the clamp, so that it is above or below the plane of the inner surface of the V clamp. In a preferred embodiment of the invention, two blades are positioned one in each jaw. The blade is placed so that the sharp part of the blade is at least 0.001 mm. above or below the plane of the inner surface of the clamp.
The lateral distance of the blade, or blades, from the V clamp, can be the width of the jaws, or half of it if we use two clamps. The closer the clamp is to the blade, the shorter the stump which remains on the severed edge of the cord.
The scissors must be designed so that even when the clamps are completely closed, the two handles on the other side of the pivot, do not reach each other. The scissors must not allow the handles to reach their closed position, if the clamps are not yet closed
The umbilical cord is placed between the two open jaws containing the blade or blades which are xe2x80x9chiddenxe2x80x9d by the V clamp or the two V clamps. When pressure is exerted on the scissors handles, the arms of the V clamps are closed and locked together with the umbilical cord squashed between them At this stage the blades on the jaws do not yet reach the cutting position as they are still beyond the middle plane of the V clamps. The handles on the other side of the scissors pivot have reached the end of their movement, with the jaws partly closed, but still have a way to go. However, they are prevented from further movement by the closed V clamps, which do not allow the jaws to come closer to each other.
At this stage, the V clamps are pushed forward axially with respect to the jaws, proportionate to their previous position. This proportionate movement is achieved by pushing the V clamps forward releasing and detaching the clamps from their initial fixed position in the jaws. The movement of the V clamps out of their grip, allows the jaws to move closer and close fully, enabling further moving of the handles towards their closed position, while simultaneously enabling the blades to sever the tube.
The movement of the V clamps out of the grip can be achieved by using a spring that is activated by pressure on the handles and results in pushing the clamps. This action will be explained in detail later. Another way to release the V clamp from their grip can be achieved by a tab near the scissors pivot, close to the arch of the V clamp base. The tab is designed so that it is not even, and when the handles move towards each other, it pushes the base of the V clamps forward.
Release of the clamps from the cradle can also be achieved by use of a wedge, or wedges, on the jaws. The wedge will push the V clamps out of their grip by entering between the V clamp and the jaws pushing them far from each other, thus releasing them from the grip.
In the above-described invention, the attendant will place the umbilical cord between the two V clamps in the jaws and close the handles in a continuous scissoring moving action until the cord is severed. The movement of the handles will first grip, clamp and squash the cord, then move the clamp forward out of the cradle closing the jaws completely, and sever the cord by means of the blade or blades. The attendant, while moving the handles will perform one continuous action, whilst on the jaws end, three consecutive actions have been performed: clamping the cord, moving the clamp forward to close the jaws completely and cutting the cord.
The fastest current procedure (not using our invention), will require 6-7 seconds for cord severing whilst our novel procedure will take 1 second. This will provide the attendant with an opportunity to suction the infant""s air passage virtually before the infant""s first breath or at most its second breath, thus preventing material from reaching far into bronchi, by means of direct tracheal suctioning by the attendant.
As stated before, the basic idea in our invention is to use a scissors-like device to perform clamping of the umbilical cord, using regular and commonly used V shaped clamps in the art of clamping the umbilical cord. In the same action of movement of the handles at the other side of the pivotxe2x80x94after the V clamps are securely closed and the posterior handles have reached their final position for clamping, the clamps are detached from their first position by moving them forward. The first position does not enable the blades to sever the cord, only the detachment and advancement of the V clamps from their position permits the blades to proceed with their severing action and cut the cord.
The above-described phenomena can be achieved by adding to the device, a push spring which will detach the V clamps after they are securely closed.
Another way to achieve the detachment is by means of a protrusion-tab placed close to the V clamps that detach the V clamps permitting the continuation movement of the blades to cut the cord. The spring or the protrusion can be placed near the base of the V shaped clamps, which will push the V clamps forward.
Another way is to use a wedge or wedges on the bases of the jaws that hold the V clamps near the blades; the wedge, when the V clamps are closed, will move the V clamps to the side. By moving to the side, the V clamp is detached from its grip, thus permitting passage of the blades and for cutting the umbilical cord clamp.
Another possibility is to use the spring or protrusion-tab system with the wedge on the scissors jaw. This combination will secure the cutting of the umbilical cord, only after the V clamps are securely closed, and the wedges, pushing the clamp to the side, will facilitate the release of the clamps from the device.